Carpenter&#39;s square.



No. 870,584. l PATENTBD NOVVlZ,l 1907. M. C. POST.

CARPENTERS SQUARE. APPLICATION FILED APR. 15, 1907.

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MARVIN C. POST, OF BROOKFIELD, MISSOURI.

CARPENTERS SQUARE.

Speeiiication of Letters Patent.

Patented Nov. 12, 1907.

Application filed April l5. 1907. Serial No. 368,198-

To all whom 'it may concern:

Be it known that I, MARVIN O. Pos'r, a citizen of the United States, residing at Brookfield, in the county of Linn and State of Missouri, have invented certain new and useful Improvements in Carpenters Squares, of which the following is a specification.

My invention relates to carpenters tools and refers especially to thatv class of devices termed folding squares.

The chief objects oi my improvement are to provide a connecting hinge for the limbs or blades'of an ordinary square that will enable the said blades to be folded upon each other until they lie parallel and in apposition, thus permitting the tool .to be conveniently carried in a box'or chest; to furnish a strong hinge so constructed as to preserve the proper relation of theA blades with reference to their mutual plane; and to provide locking means for retaining the parts in their extended or operative position, said locking means having permanent Connection with the instrument thus preventing their loss or misplacement,

Further objects of my invention are to produce a folding square that will present a continuous edge along either margin when in extended position and in which both internal and external angles are intact when the square is in its operative position.

I accomplish the above objects by the employment of the device illustrated in the accompanying drawing which forms a part of this specification and in which:

Figure I is a side view of a portion of a carpenters square to which is applied my improved method of joining the blades so that the latter are adapted to be folded together, or locked in extended position; Fig. 2 shows the parts of the square in folded position; Fig. 3 is an edge view of the joint ends of the separated members, and Figs. 4 and 5 are views ofthe pivot screw and one of the locking rivets, respectively.

Referring to the drawing in detail, the numeral 6 indicates the larger and 7 the smaller blade of a carpenters square, the dimensions of which, as well as the graduations marked thereon, are the same as in one of ordinary rigid construction. Upon opposite sides of the blades and formed integral therewith are hinge joints or ears 8, said ears being constructed by removing one half the thickness of the stock as shown at 9 by milling or other available method of machining. As shown in the drawing, the ear which is integral with the short blade 7 projects from its side to correspond with the companion ear of the long blade 6, extending from the inner edge of said blade 7 to a distance equal to a diameter of said ear.. The ear formed upon the longer blade 6, touches the inner margin of said blade, and as the diameter of the ear is less than the width of the said blade 6 a projection or shoulder 9*L is formed on both blades, which engage to form a limiting stop when the members are extended. This construction has the advantage of making the longer limb 6 shorter than it would otherwise be, such shortening being equal to the v width of the blade 7, and the folded device will thus take up that much less space in length when placed in the chest or kit. At the center or curvature of the ears a hole is drilled and countersunk on both sides of the assembled parts to receive a pivot which may be a simple rivet headed flush with the surface on either side to forni a center upon which the blades may turn. I prefer, however, to make this center'in the form of a screw l0 with a lock nut l0*1 to take up lost motion, both the head and nut being furnished with slots to receive a screw driver.

Upon opposite sides of the instrument and diametrically across the ears are located locking rivets 1l each rivet having a head shaped like that of a screw to fit a counter-sunk hole l2 in the blade one edge oi the said head being cut away, as shown at 13, to permit the head to pass the margin of the ear when said rivet is given a half turn from its locking position by a screw driver, thus permitting the device to be folded as shown in Fig. 2. The side of the rivet head opposite to the mutilation I3, is received in a notch 14 cut in the periphery of the ear with the same operation thatforms the counterbore 14. v

It will be understood that the rivets and pivot screw will be formed with their heads flush with the metal so that the sides ofthe tool will present smooth surfaces.

vWhen the square is expanded to its operative position and the locking rivets turned until then` intact margins engage the notches 14 the shoulders 9 being in firm engagement with each other, the limbs of the instrument will be practically as rigid and immovable as if made of a single piece.

Having thus described my invention I claim:-

1. A folding square composed et' two blades pivotally connected, one blade havingl a shouldered lateral hinge member and the other blade furnished with a shouldered end hinge member. said members having registering notches, locking rivets secured to said blades respectively and on opposite sides of the square, and adapted to engage the notches in the margins of saidv hinge members, each of said rivets having a mutilated head to permit the latter when turned to release its respective hinge member and allow the said blades to be folded.

:2. A folding square. including a larger blade having a hinge member projecting from its end, a smaller blade furnished with an integral lateral hinge member, said members having registering notches, a pivot connecting said members and lockingiivets secured to said blades and adapted to engage the notches in the margins ot' said hinge members, each of said rivets having a head cut away upon one side to permit the latter when turned to release its respective hinge member and allow the said blades to be turned upon the connection pivot.

In testimony whereof I atx my signature in the presence ot two witnesses.

MARVIN C. POST.

Witnesses WAL'rnn BRowNnLL, H. W. CRAIG. 

